@Lukas Kotulac - Thanks for the question and using MS Q&A platform.
Based on the documentation you provided, it seems that you need admin access to the Databricks account to create unity catalog resources.
In order to successfully complete you need to meet the prerequisites as metioned in the document.
In case, if you still have question, please report an issue here: https://github.com/databricks/terraform-provider-databricks/issues
Hope this helps. Do let us know if you any further queries.
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